Title: Transmission of Prestressing Force to Concrete by Bonded Fiber Reinforced Plastic Tendons

Author(s): A. Nanni, T. Utsonomiya, H. Yonekura, and M. Tanigaki

Publication: Structural Journal

Volume: 89

Issue: 3

Appears on pages(s): 335-344

Keywords: bond stress; fibers; prestressed concrete; pretensioning; strain gages; stress transfer; Structural Research

DOI: 10.14359/2976

Date: 5/1/1992

Abstract:
Transmission of prestressing force to concrete by bonded fiber reinforced plastic (FRP) tendons made of braided epoxy impregnated aramid fiber was examined by experiment. Beams 4-m long and 12 x 21 cm in cross section were fabricated using different sizes and numbers of tendons, and varying surface conditions(adhered sand) and initial prestressing force. The test consisted of the nondestructive measurement of strain variation in the tendons (by strain gages) and in concrete (by contact points) at both ends of each beam before, during, and after tendon release. Transfer length is mainly affected by adhered sand on the tendon surface and by tendon size. Friction resulting from the wedge effect is the principal component of the transfer bond stress. Results showed significant differences with the case of seven-wire steel strand. Recommendations are made for values of transfer length to be used in field applications.